Object Attribute Lists

Description

These functions access an object's attributes. The first form below returns the object's attribute list. The replacement forms uses the list on the right-hand side of the assignment as the object's attributes (if appropriate).

Usage

attributes(obj)
attributes(obj) <- value
mostattributes(obj) <- value

Arguments

Details

Note that some attributes (namely class, comment, dim, dimnames, names, (from R 2.4.0) row.names and tsp) are treated specially and have restrictions on the values which can be set.

Attributes are not stored internally as a list and should be thought of as a set and not a vector. They must have unique names (and NA is taken as "NA", not a missing value).

The mostattributes assignment takes special care for the dim, names and dimnames attributes, and assigns them only when valid whereas an attributes assignment would give an error if any are not.

The names of a pairlist are not stored as attributes, but are reported as if they were (and can be set by the replacement method for attributes).

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth \& Brooks/Cole.

See Also

attr.

Examples

x <- cbind(a=1:3, pi=pi) # simple matrix w/ dimnames
attributes(x)

## strip an object's attributes:
attributes(x) <- NULL
x # now just a vector of length 6

mostattributes(x) <- list(mycomment = "really special", dim = 3:2,
   dimnames = list(LETTERS[1:3], letters[1:5]), names = paste(1:6))
x # dim(), but not {dim}names